I've seen this referenced on forums several times, but never a concise report on how they work. I decided to try it myself: cut wads from cheap plastic containers, loaded 3gr promo shotshell powder (I loaded as if it were 700-X, which some of it almost certainly was; production loads will use known powder), placed 8 grams of promo shotshell shot (~130gr, or to the top of the .357 case), and snugged the smaller half of a 000 gelatin capsule around the shot (believe large half will be useful in larger caliber projects). Overall, would say this worked well: had to slit the capsules with sharp scissors to just under the curved end since they measure ~.360"+ and do not slide into the brass easily, but did not need any crimp to keep the capsule secure. Any thoughts? I know that loading with unknown powder is a big no-no but figured that a mid-range .38 load in a .357 gun would likely be safe. Will report back after testing, hopefully later this week.